The mean and variance of a data of 10 observations are 10 and 2, respectively. If an observation in this data is replaced by , then the mean and variance become 10.1 and 1.99, respectively. Then equals.
- (A)10
- (B)15
- (C)5
- (D)20✓ Correct
Answer: (D)
Solution
From mean and variance over values, and . Replacing by raises the mean to , so , giving . The new variance gives , so . Then with gives .
JEE Main · 2026 · 24 Jan 2026 · Shift 1 · Single correct option